The Flamanville EPR vessel head replacement to be postponed?

Framatome, in conjunction with the operator EDF, has asked the French nuclear safety authority (ASN) to postpone the deadline for replacing the vessel head of the Flamanville EPR reactor. This request was investigated by the ASN and led to a public consultation from March 10 to 31, 2023.

In its January 2023 statement, the ASN said that Framatome, in conjunction with the operator EDF, had submitted a request at the end of December 2022 to extend the deadline for changing the cover of the Flamanville EPR reactor vessel.

As a reminder, carbon segregation on the cover and bottom of the vessel has been identified as being higher than specified, reaching 0.3% locally compared to 0.22% [1]. However, this poses a minor safety problem. This is why the ASN, in its decision of October 9, 2018, requested the implementation of a follow-up for the vessel bottom.

But concerning the cover, the ASN stated, “the technical feasibility of similar controls […] is not acquired and therefore that in the current state of knowledge, the use of this cover must be limited in time.” It was planned to replace the reactor vessel cover during the first shutdown in 2024. Since then, the schedule has been shifted, and fuel loading is now scheduled for the first quarter of 2024. Thus, the request aims to adjust the agenda not to shut down the reactor before its first operating cycle ends. According to the ASN, this choice has several advantages.

Synchronization of schedules has several advantages

In its annual report, the ASN was reassuring in emphasizing that it had studied the use of this cover for several cycles without any difficulties. Moreover, “the postponement requested by the manufacturer Framatome will lead to a duration of use of the cover of the order of 18 months, i.e., less than that envisaged when the ASN made its decision of October 9, 2018, mentioned above, which, given the date then envisaged for the startup of the reactor, was about four years,” the ASN [2] states.

In addition, “the elimination of a shutdown during the first cycle dedicated to the replacement of the cover will prevent a possible interruption of the reactor startup tests, avoid the performance of sensitive operations of shutdown and restart of the reactor and reduce the collective exposure related to additional operations, which are favorable elements in terms of nuclear safety and radiation protection,” adds the authority.

Public consultation

The ASN is making available to the public the application file submitted by Framatome and the draft decision on the modification of the one of October 9, 2018. It has invited citizens to express their views on the subject between March 10 and March 31, 2023.■